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<A HREF="21-1.html"><IMG SRC="images/bprev.gif" WIDTH=20 HEIGHT=21 ALT="Previous file" BORDER=O></A><A HREF="noframes.html"><IMG SRC="images/btop.gif" WIDTH=56 HEIGHT=21 ALT="Top of Document" BORDER=O></A><A HREF="booktoc.html"><IMG SRC="images/btoc.gif" WIDTH=56 HEIGHT=21 ALT="Contents" BORDER=O></A><A HREF="tindex.html"><IMG SRC="images/bindex.gif" WIDTH=56 HEIGHT=21 ALT="Index page" BORDER=O></A><A HREF="21-3.html"><IMG SRC="images/bnext.gif" WIDTH=25 HEIGHT=21 ALT="Next file" BORDER=O></A><DIV CLASS="DOCUMENTNAME"><B>Rogue Wave C++ Standard Library User's Guide</B></DIV>
<H2>21.2 Fundamental Datatypes</H2>
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<P>The Standard C++ Library describes a specific type by providing a specialization of the<SAMP> numeric_limits</SAMP> template for the type. Static member functions and static constant data members then provide information specific to the type. The Standard C++ Library includes descriptions of the fundamental datatypes given in <A HREF="21-2.html#Table&nbsp;21">Table&nbsp;21</A>.</P>
<H4><A NAME="Table&nbsp;21">Table&nbsp;21: Fundamental datatypes of the Standard C++ Library&nbsp;</A></H4>
<TABLE BORDER="1" CELLPADDING="3" CELLSPACING="3">
<tr><td valign=top><B><SAMP>bool</SAMP></B>
</td><td valign=top><B><SAMP>char</SAMP></B>
</td><td valign=top><B><SAMP>int</SAMP></B>
</td><td valign=top><B><SAMP>float</SAMP></B>
</td></tr>
<tr><td valign=top colspan=1 rowspan=6>&nbsp;
</td><td valign=top><P CLASS="TABLE"><SAMP>signed char</SAMP></P>
</td><td valign=top><P CLASS="TABLE"><SAMP>short</SAMP></P>
</td><td valign=top><P CLASS="TABLE"><SAMP>double</SAMP></P>
</td></tr>
<tr><td valign=top><P CLASS="TABLE"><SAMP>unsigned char</SAMP></P>
</td><td valign=top><P CLASS="TABLE"><SAMP>long</SAMP></P>
</td><td valign=top><P CLASS="TABLE"><SAMP>long double</SAMP></P>
</td></tr>
<tr><td valign=top colspan=1 rowspan=4>&nbsp;
</td><td valign=top><P CLASS="TABLE"><SAMP>wchar_t</SAMP></P>
</td><td valign=top colspan=1 rowspan=4>&nbsp;
</td></tr>
<tr><td valign=top><P CLASS="TABLE"><SAMP>unsigned short</SAMP></P>
</td></tr>
<tr><td valign=top><P CLASS="TABLE"><SAMP>unsigned int</SAMP></P>
</td></tr>
<tr><td valign=top><P CLASS="TABLE"><SAMP>unsigned long</SAMP></P>
</td></tr>
</TABLE>
<P>Certain implementations may also provide information on other datatypes. Whether or not an implementation is described can be discovered using the static data member <SAMP>is_specialized</SAMP>. For example, the following is legal, and will indicate that the <B><I><A HREF="../stdlibref/basic-string.html">string</A></I></B> datatype is not described by this mechanism.</P>

<UL><PRE>
std::cout &lt;&lt; "are strings described " &lt;&lt;
   std::numeric_limits&lt;string&gt;::is_specialized &lt;&lt; std::endl;
</PRE></UL>
<P>For datatypes that do not have a specialization, the values yielded by the functions and data members in <SAMP>numeric_limits</SAMP> are generally zero or <SAMP>false</SAMP>.</P>

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